Alzheimer's vaccine 'in a patch'

A patch which delivers a vaccine against Alzheimer's disease through the skin has been shown to be safe and effective, a study has found. University of South Florida researchers reported the patch was able to clear brain-damaging plaques from mice. They say it may be a simpler way of protecting people against the disease than a conventional injected vaccine.

UK experts said the Proceedings of the National Academy of Sciences study was "potentially very exciting".

Alzheimer's is linked with the build up of a protein called beta amyloid in the brain, where it clumps together to form damaging plaques.

The vaccine - given transdermally - works by triggering the immune system to recognise beta amyloid protein, attack it and break it down. Earlier research into an injectable Alzheimer's vaccine was suspended indefinitely when the initial clinical trial caused brain inflammation and death in a small percentage of patients.

It also triggered an autoimmune reaction, which occurred when immune cells turned on proteins produced by the body in response to the vaccine. In this study, the researchers tested the skin patch on mice with an age-related brain degeneration similar to Alzheimer's. They found it did not have the same toxic effects as the injected vaccine.

The team suggest that specialised immune cells present in the skin called Langerhans may direct the body to respond positively to the vaccine.

Jun Tan, of the University of South Florida department of psychiatry, who led the study, said: "While many groups have shown vaccinating against the beta amyloid protein can reduce Alzheimer's-like pathology including certain cognitive deficits, this study is the first to demonstrate that immunisation using the skin may be effective."

The team will now carry out further research to see if the vaccine can curb memory loss in Alzheimer's mice as well as reduce their plaque burden. Dr Tan added: "If those studies show clear cognitive benefits, we believe clinical trials to evaluate a beta amyloid skin patch or topical cream in patients with Alzheimer's would be warranted."

Clive Ballard, director of research at the Alzheimer's Society said: "There has been tremendous interest about developing a vaccine to treat Alzheimer's disease. Although side effects have been a problem in initial human vaccine studies, this new study is potentially very exciting. The prospect of a practical and non-invasive vaccine delivered through this new method is particularly welcome. However, more research and evaluation is now needed to investigate whether it is a safe and effective method to deliver the vaccine in humans."